On my way out of Yellowstone, It was already getting late and I knew that I wasn't going to drive all the way to Glacier National Park that night. I had no internet to search for where to stay, so I started driving in the direction I needed to go. Along the way I saw a billboard for the Lewis and Clark Caverns State Park, which sounded intriguing. I ate dinner in the small town of three forks and had just enough internet to search how far away I had to go to find this park, and it turns out it was only about 30 minutes away.
They had a fantastic campground and the next day I got up early to explore the caves. I took a two hour guided tour and it was fantastic. First you have to hike up about 3/4 mile to the cave entrance, but once inside you get taken to a new world. In order to navigate the caves, you have to crawl, squeeze, duck walk, and even slide (they carved a short slide into the stone to get through one section), it was unlike anything I've ever done before. During the tour, you descend about 300 feet into the depths of the mountain. Luckily, they knew people did not like hiking back out of the caves, so years ago they blasted a nice tunnel through the mountain to get back to the outside world.
I highly recommend that anyone traveling through the area takes the time to visit the park. It's well worth it.
After the caves I finally got started towards Glacier National Park.